We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Long-term exposure to biodegradable polylactic acid microplastics promotes Microcystis aeruginosa proliferation
AI summary Read the abstract
Researchers conducted a 45-day co-culture experiment exposing the bloom-forming cyanobacterium Microcystis aeruginosa to biodegradable polylactic acid microplastics. PLA-MPs promoted algal growth and photosynthetic activity and altered nutrient cycling, suggesting that biodegradable plastic particles can unexpectedly fuel cyanobacterial blooms in freshwater ecosystems.
Biodegradable plastics, such as polylactic acid (PLA), are widely considered as sustainable alternatives to petroleum-based polymers; however, PLA generates polylactic acid microplastics (PLA-MPs), which raises ecological concerns in freshwater ecosystems. In this study, we investigated the responses of Microcystis aeruginosa to PLA-MPs (1, 10, and 50 mg/L) across a 45-day co-culture experiment. We found the PLA-MPs initially inhibited algal growth (days 18, 27) through mechanical damage and shading effect, as indicated by the activation of oxidative stress system, heterogeneous aggregation of algae cells and PLA-MPs, and down-regulated expression of light reaction in photosynthesis. However, during stabilization (days 36 and 45), PLA-MPs promoted growth in a dose-dependent manner, with Chl-a content in the 1, 10, and 50 mg/L PLA-MPs added groups reaching 1.12, 1.36, and 1.44 times that of the control, respectively. And the particle size of algal cell aggregates increased upon PLA-MPs exposure. In response to the dual negative and positive effects of PLA-MPs during 45 days of co-incubation, M. aeruginosa exhibited dynamic biological responses. This demonstrated that the intracellular MDA content, SOD activity, CA content, MC-LR content, as well as extracellular MC-LR content and EPS (polysaccharides and proteins) content exhibited increases before day 27 followed by a decrease after day 27, which correspond to the two distinct phases of M. aeruginosa growth inhibition and promotion. Especially, the expression of proteins involved light reaction in photosynthesis was inhibited in the on day 27, while it recovered and was promoted on day 45. Our results confirm that PLA-MPs have a long-term effect on M. aeruginosa growth, providing fundamental theoretical guidance for investigating the ecological and environmental impacts of PLA-MPs in aquatic ecosystems.
More Papers Like This
Revealing the environmental hazard posed by biodegradable microplastics in aquatic ecosystems: An investigation of polylactic acid's effects on Microcystis aeruginosa
AI summary Read the abstract
Researchers tested whether biodegradable polylactic acid (PLA) microplastics are safer for aquatic life than traditional plastics by exposing the cyanobacterium Microcystis aeruginosa to them for 63 days. Surprisingly, PLA microplastics actually promoted algae growth despite causing oxidative stress and cell damage, which could fuel harmful algal blooms. This suggests that so-called biodegradable plastics may still pose environmental risks and are not necessarily a safe alternative in aquatic ecosystems.
Effects of micro-sized biodegradable plastics on Microcystis aeruginosa
AI summary Read the abstract
Researchers tested how micro-sized biodegradable plastics made from polylactic acid and polyhydroxybutyrate affect a common freshwater cyanobacterium. They found that even biodegradable microplastics inhibited the growth and photosynthetic activity of the organism, though to a lesser extent than conventional plastics. The study suggests that switching to biodegradable plastics does not eliminate the risk of microplastic-related harm to aquatic microorganisms.
The competitive advantage of Microcystis aeruginosa over Scenedesmus obliquus weakened by exposure to polylactic acid microplastics
AI summary Read the abstract
Researchers studied how polylactic acid microplastics affect the growth competition between the toxic cyanobacterium Microcystis aeruginosa and the green alga Scenedesmus obliquus. They found that while PLA microplastics promoted the growth of both species, they substantially reduced toxin production in Microcystis, weakening its competitive advantage. The study suggests that biodegradable microplastics may alter harmful algal bloom dynamics by changing the balance between competing phytoplankton species.
Acute Toxicity Effects of Aged Polyethylene and Polylactic Acid Microplastics on Microcystis aeruginosa: Growth and Oxidative Stress Response
AI summary Read the abstract
Researchers compared the acute toxicity of aged polyethylene (conventional plastic) and polylactic acid (biodegradable plastic) microplastics on the cyanobacterium Microcystis aeruginosa. Aged PLA microplastics inhibited algal growth more than aged PE, and UV-aged particles were more toxic than heat-aged ones for both plastic types. The study suggests that biodegradable plastics may not be less harmful than conventional plastics once they begin degrading in the environment.
Ecological risk analysis and prediction of microplastics' effects on Microcystis aeruginosa in freshwater system: a meta-analysis approach
AI summary Read the abstract
This meta-analysis found that micro- and nanoplastics can both inhibit and stimulate the growth of Microcystis aeruginosa — a harmful algal bloom cyanobacterium — depending on particle size and degradability. Smaller, degradable plastics tend to promote algal growth, suggesting microplastic pollution could worsen toxic algal blooms in freshwater systems used for drinking water.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.